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Rechargeable Torch Light repair

Discussion in 'Repairing Electronics' started by indigo, Nov 22, 2017.

  1. indigo

    indigo New Member

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    Hi Les Jones

    Can I put zener diode at C2?
    I've marked with yellow rectangular.
    Is it correct polarity? or it can be put any polarity?
    IMG_20171124zener.jpg

    What voltage should I use?
     
    Last edited: Dec 3, 2017
  2. Les Jones

    Les Jones Well-Known Member

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    A zener in parallel with C2 is a good way to limit the voltage. Either a 12 volt or 15 volts zener should be OK. It should be at least 2 watts power rating. You have the polarity correct. I think you should also raplace C1 as it could be breaking down as JimB suggested. I would reccomend a capacitor rated at above 250 volts AC (Rather than the 400 volt DC rating.) and X rated. (This indicates that thay are safe for this sort of application.) I think this capacitor is 1.5 uF from the 155j in the part number.

    Les.
     
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  3. indigo

    indigo New Member

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    I've replaced the C1 with CL21 105k 250v (printed on) that one from the right circuit.

    View attachment 109406

    That circuit is also from the rechargeable torch light with FM radio. Radio is not funtion and I took from that.
    After replacing the out put is still the same. Without load 80V and with load 10V or 12V. But C2 will explode within 5minutes.
    That's why I'm planning to put zener.

    Can u please give me suitable C1 part number?
     
  4. dave

    Dave New Member

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  5. Les Jones

    Les Jones Well-Known Member

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    Either of these capacitors would be a suitable replacement for the original 1.5 uF capacitor. This would give a charging current of about 100 mA which in my opinion would be too high. This is only a guess as you have not given the full specifiication of the battery. If you used a 4.7 volt zener diode this would would limit the charge voltage to a more suitable level. (A 1 watt rating for a 4.7 volts zener should be enough.)

    Les.
     
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  6. indigo

    indigo New Member

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    Thank you Les Jones .

    I'll try to find that capacitor and tell you the outcome.
     

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